Picture of Homemade Plastic
This is a quick and simple method for making your own general-purpose plastic. The constituent ingredients are milk and vinegar. That's it. The total cost is less than $10, possibly less than $5 if you can get a good deal.

The plastic is moldable, and has a consistency of soggy cheese (I certainly hope I never encounter cheese that's anything like this!). When all is said and done, it should take you about 10-15 minutes to make the plastic (less if you make a small amount), 10 minutes of cleanup, plus 2+ days to allow the plastic to dry. As always, your milage may vary.

As for the final product's strength and whatnot, I would classify it as "okay." If you roll it thin (as I did in this instructable), it can easily be snapped in half, though it will probably survive a small drop on to carpet. Thicker pieces seem to be more resilient against average abuses - no problem dropping on to carpet, and if it's thick enough, you wouldn't be able to snap it in half. A blow from a hammer or other such object would quickly shatter it, though.

All in all, I would say this is mostly useful for folks looking for a fast and dirt cheap alternative to much better products available to the average joe. It's definitely not for something that will be handled on a daily basis - good enough for light decor, not much else.

This is my first Instructable, so bear with. Constructive criticism is always welcome!
1-40 of 276Next »

Ok, so I have looked through pretty much all the comments and come to the conclusion that this is NOT cheese because cheese is made with the acids produced by different kinds of bacteria. However is IS pretty much cottage cheese or paneer, both edible and very spoil-able substances. So my question is, how the heck is this not suppose to mold and go bad?? I tried it and mine molded after a couple days.

You could make capacitors with this. It will have a very high dialectric constant. If you add a bit of plaster into the mix, it will be ideal Bakelite. Bakelite Capacitors were some of the highest value capacitors around back in the day (approx. 60s).

abishait6 months ago
Why is it that green stuff (those are molds, aren't they?) start growing on the one I made? Is it the amount of vinegar or milk or what??
skooterv26 years ago
I play airsoft a lot and I play with some people with guns that hurt pretty bad...and this may sound weird but I was wondering if I made this thick enough do U think it could withstand some pretty hard blows like from guns shooting at 400+ fps... TYVM
btw is there anything I could add to make it stronger?? And if u could e-mail me back on this I would greatly appreciate it
cd41 skooterv26 years ago
well this maybe the dumbest thing i ever suggested but you could try putting pencil lead(graphite) in it it is carbon and they add carbon to steel to make it harder and fabric or something but thats just what i would try
tbh-1138 cd412 years ago
Steel is iron alloyed with carbon. Putting pencil lead in casein would be like putting pieces of steel in lead to make it harder. It won't be much better than it would without the graphite. Something like fabric or paper pulp could work, though, and I don't think it would set any faster. Fibers make things stronger.
KurtB2 tbh-11389 months ago

pencil lead is not lead at all, its graphite, which is carbon.

Cool Idea, But how much milk are you willing to spend on this?

Imagine, an army of Cheese-weilding warriors!
Use the Cornstarch, water, and oil plastic its hard and not too brittle
make a thin sheet then cover the back with glue and fabric
Coffeebot (author)  skooterv26 years ago
It might work, if you make it thick enough. It's pretty brittle in thinner layers, and as such, wouldn't do well as body armor.

As for "making it stronger" (your note below), you could possibly add some fabric, of some sort to strengthen it.
Thank you.I really appreciate u getting back to me so quickly. How would u suggest adding fabric to it? Like just adding it in randomly when molding or what? Sorry I have no idea about that. Thanks again
Coffeebot (author)  skooterv26 years ago
Not "randomly" but yes, while you mold it. Probably sandwiching the fabric between two layers of casein would work You'll need something fairly porous -- much looser than cheesecloth, I think. The reason is because of the thick, chunky consistency of the casein, you'll need a lot of gaps between threads in order for two sides to join together.
sorry another question if u don't mind. The juice that drains out of the casein and into a large pot, can u stir it and make that into plastic, too?
thank you And one last question if u don't mind. How thick would you recommend making it? Obviously you have more experience with casein then me. Tyvm again.
deej111 months ago

how is it to heat? can i make a tobacco pipe out of it?

sudanione4 years ago
how can make it transparent
sehrgut sudanione11 months ago

As a colloidal material, protein glues can never be made truly transparent. However, some (like isinglass) approach it, especially in thin pieces. (Isinglass and other gelatine-type glues are not waterproof without denaturation by tannins, bichromate salts, formaldehyde, or the like, though.)

You can't.
sehrgut11 months ago

What you've made is (besides being "cottage cheese") traditional carpenter's glue. If you want to encourage faster curing and decrease shrinkage, you can use fillers such as sawdust (depending on coarseness, will be similar to "wood composite" plastics); chalk or marble dust, gypsum, slaked lime, or slaked plaster (consistency much closer to plastics like bakelite); or even sand (for a more "concrete" texture). Fillers will also decrease the brittleness of the material at the expense of hardness. Plasticisers such as glycerine, honey, or molasses (if you're trying to stay completely "appropriate technology"); or a mid-weight PEG (if you don't mind a bit of modernity) will also let you modify its properties significantly.

decat21 year ago

what you just made is 'home made cottage cheese', farmer's cheese, paneer,, whatever the local people would call it ... exactly the same recipe up until when you dried it or ironed it. Same exact recipe all farm mothers made for years before they had stores to buy it from... ;) I still make it, and eat it...sometimes I add some cream to cream it and some salt or spices for more taste... I suppose you can dry it and it would be kinda plasitcky... I would add some fungicide to it so it wouldn't mold though. :)

enelson81 year ago
What is the approximate density of this plastic? D=M/V
LiftAndLove2 years ago
Does it stink? and could it be made to replace plastic pellet gun pieces, if the previous were plastic too?
fretted2 years ago
Make Your Own Casein Glue from Milk
1. Heat some skimmed milk (do not let it boil)
2. Add about 3 teaspoons of vinegar (an acid) to the milk and stir slowly until the milk
separates into curds (solid sticky bits) and whey (clear liquid)
3. Pour the curds and whey through a tea strainer or sieve to collect the curds
4. In a container, add a little bit of bicarbonate of soda or milk of magnesia (alkali)
5. You should now have a sticky white substance called casein (milk protein). This can
be used as a binder in paint – just add some pigment!
What you've made right there is what we in India call 'paneer' we use it in curries n stuff its delicious, its a kind of cheese, and i'm not sure its a plastic.
You are right that what he has made is Paneer. (Here in the states it is called Cottage Cheese.) However, do a google search for Casein Plastic and you will find that it was a widely used plastic for making buttons, knitting needles, ink pen cases etc. in the early 20th century. It is a polymer by definition and therefore technically a plastic. When used in manufacturing, it would be treated with formalin to retard an bio-degradation. Casein was also a widely used medium for paint.
fqian yan3 years ago
will mold grow on it in the process of drying?
billraymond3 years ago
Are you sure this is truly casein?? My understanding is that casein is precipitated from milk by rennet, not heat. Heating whey with vinegar or other acidifier creates ricotta, which is not a cheese, as it contains no casein, but is rather the precipitated albumin and other (not casein) proteins. Galalith is made from casein and must be fixed in a formaldehyde bath; it is not moldable.
CamoBedding3 years ago
I had no idea you could make home made plastic.
Is the Formaldehyde + Milk Galalith plastic brittle? can it keep a sharp point? will it bend? i will definitely experiment with casien

Any other chemistry suggestions would be welcome.
I want to use casien to make a DIY arrowpoint. I fear that Casien plastic will be

far, far too brittle. is this true?
wow very interesting.
It is very interesting to make plastic out of milk.
But what are the advantages of extracted plastic?????
Although it contains caesin, would it cause any harm if someone eats it??????
Please do reply as soon as possible......
This is cheese. Period. Fromage. Queso. Formaggio. Cheese.
Ah-yup. And while it is plastic by nature, a much superior plastic (harder, more resilient to shock, more resistant to mold) can be made by "dissolving" styrofoam in acetone.
bpfh Broom3 years ago
This is relevant to my interests. Please explain more :)

Just dissolve the styrofoam (polystyrene?) in acetone to a thick goo, mold and leave to dry in a remote area as not to get her indoors all worked up about the acetone smell?
Broom bpfh3 years ago
Pretty much, bpfh. It's a weird, fun process: the acetone "eats" up the styrofoam like a hungry monster, turning a huge amount into a small "sediment" of sticky plastic.

It can take days & days for it to dry on its own, and of course it gives off acetone fumes the whole time. There's no chemical reaction - the acetone just dissolves the styrene in the the mostly-air styrofoam (emphasis on "foam"!), and then gets trapped inside the drying skin of the finished plastic if it's thick, slowing down the drying.

It shrinks somewhat in the drying process, but never (IME) breaks. Also, it seems to change if left in the acetone for a long time, becoming resistant to shape change, so it's best to mold it immediately after dissolving the styrene.
Broom Broom3 years ago
BTW, an entire styrofoam cooler can be dissolved into about a pint of styrene, if you want an idea of how much contraction goes on in the "eating" portion! Don't have any stats on the drying shrinkage, but it's more like 1-15%... something reasonable.
bpfh Broom3 years ago
Thanks for this update! I may try this in the next few weeks!

My project is quite simple: I have a motorbike where you cannot really get any plastic parts for it anywhere for love or money, and I need new wingmirror shells.

So either you are very very very lottery jackpot winning lucky if you find a part on ebay, or you cast it yourself.... I was originally thinking about resin casting, but resin costs a fortune. Casein seemed a good idea but being organic , I'm not sure about resistance to mold and fungus, and styrene seems easy enough to make... even if it may be more fragile than standard ABS plastic, I'm not very worried. You just need a ton of styrofoam to get a handful of goo :)

The other alternatives, like Sugru cost too much to be cost effective, and low temperature thermoplastics could melt if being left in the sun too long, so this method could allow me to make my prototype mirrors !


1-40 of 276Next »